Liquid filter element having keys

ABSTRACT

A filter element having a plurality of keys for actuating a locking mechanism of a valve of a filter is provided. The keys are formed on an interior side of a first end cap and extend axially inward toward a second opposite end cap. In one embodiment, the keys are integrally formed in an inner annular wall. In another embodiment, the filter media is embedded into generally flat surfaces of the end caps. The keys function to unlock the locking mechanism of the valve indicating that a filter element is being used.

FIELD OF THE INVENTION

This invention generally relates to liquid filters and more particularlyto liquid filter elements having keys for actuating valves.

BACKGROUND OF THE INVENTION

Fluid filtration systems for vehicle engines will typically include afilter housing and a filter element. It is common in such fluid filtersystems that the filter housing will incorporate a standpipe with avalve on it which when opened permits the flow of fluid through thefiltration system. It is also known that when the filter element isremoved that the valve will close to thereby prevent impurities frompassing downstream and getting into the standpipe during the filterreplacement process. While valves on standpipes do provide theaforementioned benefits, some manufacturers have elected to employtricks for actuating the valve such as shown in U.S. Pat. No. 6,495,042to Steven R. Knight in which the valve is protected by an additionallatch member. This type of arrangement has been commercially employedbut unfortunately is disadvantageous to everyone in that it increasesthe difficulty for maintenance, increases the overall costs of providingthe filtration system and has no real benefit to consumers.Nevertheless, due to the existing use of such systems, there are needsfor replacement filters for these types of applications. Additionally,there is a need for reliable, cost effective and practical filters forthese applications, including components which are easy to manufactureand assemble, to which the present invention is directed.

BRIEF SUMMARY OF THE INVENTION

The invention provides an improved filter element having keys forunlocking a valve structure. As such, the present invention provides afilter element that is configured to prevent improper filter elementsfrom being installed on a standpipe. Furthermore, the present inventionsimplifies or eliminates much of the structure previously, which reducescomplexity and manufacturing costs.

According to one embodiment, the invention provides a filter elementhaving an axially extending cylindrical ring of filter media defining aninterior cavity. A closed end cap and an open end cap are attached toopposite ends of the filter media. Each end cap has an interior sidefacing the ring of filter media and an exterior side facing away fromthe ring of filter media. The closed end cap has an inner annular wall,an outer annular wall and a disc portion that in combination define anannular well for receipt of bonding material. Cured bonding material inthe annular well secures the closed end cap the filter media. The closedend cap includes at least one filter housing mounting structure. Aplurality of keys on the inner annular wall extend axially inward towardthe open end cap. The keys form a terminating axially inner end of theinner annular wall. The inner annular wall serves dual functions inlocating keys and damming the bonding material.

In yet another embodiment, the invention provides a filter elementcomprising a cylindrical ring of filter media defining an interiorcavity. The filter media extends axially between opposite ends. A closedand an open end cap are affixed to the opposite ends of the filtermedia. Each end cap has an interior side generally facing the ring offilter media and an exterior side generally facing away from the ring offilter media. The closed end cap is formed of plastic material andincludes a disc portion with an interior surface facing the open endcap. One end of the filter media is embedded in the plastic material ofthe disc portion. A filter housing mounting structure is included on theclosed end cap. A plurality of keys are on the interior surface of thedisc portion and project axially inward from the interior surface of thedisc portion.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention and,together with the description, serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a cross-sectional illustration of an exemplary embodiment of afilter element in accordance with the teachings of the presentinvention;

FIG. 2 is a cross-sectional illustration of the filter element of FIG. 1attached to filter housing cap having the filter element uninstalledsuch that the keyed valve is in a closed position;

FIG. 3 is a cross-sectional illustration of the filter element andfilter housing of FIG. 2 having the filter element installed such thatthe keyed valve is in an open position; and

FIG. 4 is a cross-sectional illustration of an alternative embodiment ofa filter element according to the teachings of the present invention.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a first embodiment of a liquid filter element 10 inaccordance with the teachings of the present invention. The filterelement 10 may be applied to filter impurities from fluids such asfuels, lubricants, hydraulic fluids and other the like fluids used in orby engines of vehicles or engines. As illustrated in FIGS. 2 and 3, afilter housing, illustrated in simplified form, houses and protects thefilter element 10. The filter housing includes a housing receptacle 20and a housing cap 22. The housing cap 22 mounts to the housingreceptacle 20 by cooperating threads 24, 26. The housing receptacle 20is typically connected to a filter head (not shown) of the engine, or afuel pump which includes a dirty fluid port that supplies dirty fluidfrom the engine upstream of the filter element 10 and a clean fluid portdownstream of the filter element 10 that returns the clean fluid to theengine after it passes through the filter element 10. Typically, thehousing receptacle 20 and housing cap 22 are formed from aluminum, castiron, steel, plastic or other substantially rigid materials that arenon-reactive with the fluid being filtered.

The filter element 10 mounts to and partially surrounds a standpipe 30that extends axially within the housing receptacle 20. The standpipe 30includes a central cavity 34 that extends the axial length of thestandpipe 30 and serves as a clean fluid return passage. As such, thecentral cavity 34 fluidly communicates with the interior cavity 38 of afilter element 10 when installed on the standpipe 30.

The filter element 10 includes a generally cylindrical ring of filtermedia 40 that extends between a first end 42 and an opposite second end44. The filter media 40 forms the interior cavity 38. The filter media40 may be any standard filter media including preferably pleated filterpaper formed from cellulose material. The standpipe 30 extends into theinternal cavity 38 of the filter element 10, when the filter element 10is mounted to the standpipe 30.

The filter element 10 includes closed and open end caps 48, 50 fixed tothe first opposite ends 42, 44 of the filter media 40, respectively. Inan embodiment, the end caps 48, 50 are formed from molded plastic.However, one or perhaps both of the end caps 48, 50 may be formed fromother materials including metal. Additionally, while unitary one pieceend caps are illustrated, the end caps may comprise multiple pieces

In the illustrated embodiment, an interior side of the closed end cap 48includes an inner annular wall 54 and an outer annular wall 56 thatextend axially inward toward the filter media 40 and the open end cap50. The annular walls 54, 56 are coaxial with the longitudinal centralaxis of the filter media 40 and are radially spaced apart forming afirst annular channel 58 therebetween. One end 42 of the filter media 40is fixed to the closed end cap 48 within the first annular channel 58,which forms a well for holding bonding material 60, which may includeplastisol, or other similar potting material or adhesive, that fixes theclosed end cap 48 to the filter media 40. The boding material 60 sealsthe end of the filter media to the end cap 48 to prevent fluid fromshort circuiting the filter media 40. In an embodiment, the filter media40 is radially positioned proximate the outer annular wall 56 and isradially spaced apart from the inner annular wall 54, forming a gapbetween the inner annular wall 54 and the radial inner periphery of thefilter media 40. In an embodiment, the gap between the inner peripheryof the filter media 40 and the inner annular wall 54 may be greater than25% of the thickness of the wall of the cylindrical ring of filter media40.

Furthermore, the closed end cap 48 includes a plurality of mountingprongs 64 on an exterior side of the closed end cap 48 that extendaxially away from the open end cap 50 and the filter media 40. Themounting prongs 64 connect to and engage a cooperating filter mount 66of the housing cap 22 of the filter housing. The filter mount 66 forms acavity 68 that receives the mounting prongs 64. When received in thecavity 68, the mounting prongs 64 resiliently flex to secure the filterelement 10 to the cap 22. The cavity 68 may include an annular groove 70that receives a rounded head 72 of each mounting prong 64 to furthersecure the filter element 10 to the cap 22. The mounting prongs 64 arepreferably unitarily formed with the rest of the closed end cap 48. Theillustrated embodiment includes multiple mounting prongs 64, however,one of ordinary skill will recognize that any number of mounting prongsmay be used, including only a single mounting prong.

The open end cap 50 includes an inner annular wall 76 and an outerannular wall 78 that extend axially toward the filter media 40 and theclosed end cap 48. The annular walls 76, 78 are coaxial with thelongitudinal central axis of the filter media 40 and are radially spacedapart forming a second annular channel 80, which similarly forms a wellfor holding plastisol 82 for potting the second end 44 of the filtermedia 40 therein.

The open end cap 50 includes a radially inward extending sealing lip 92that defines a central aperture. The central aperture receives thestandpipe 30 therethrough and is sized to sealingly engage the outersurface 88 of a main pipe 90 of the standpipe 30 to form a radial sealtherebetween. The seal between the second end cap 44 and the standpipe30 prevents dirty fluid, indicated generally as arrows 94, from shortcircuiting the filter media 40.

The distal end of the standpipe 30 includes a keyed flow valve,indicated generally by reference number 98, that prevents fluid fromflowing through the filter housing if the filter element 10 is removedand not replaced. The standpipe 30 includes a pipe stub 100 that extendsaxially from the end wall 104 of the main pipe 90 and includes at leastone inlet hole 102 that passes through the cylindrical sidewall of thepipe stub 100. The pipe stub 100 extends through an aperture in the endwall 104 of the main pipe 90 and includes a radially extending annularflange 106 positioned within the central cavity 34 of the main pipe 90that abuts with the interior side of the end wall 104 forming a sealtherebetween. The seal prevents fluid from short circuiting a valve 98.

The valve includes a valve member 108 that circumscribes the pipe stub100 and functions to open and close the inlet hole 102. The valve member108 is configured to move axially relative to the pipe stub 100 betweena first position (FIG. 2) wherein the valve member 108 closes the inlethole 102 and a second position (FIG. 3) wherein the valve member 108opens the inlet hole 102.

To prevent fluid from short circuiting the valve member 108 in theclosed position, a pair of seals 110, 112 are axially spaced apart andhaving the inlet hole 102 interposed axially therebetween. The seals110, 12 seal the valve member 108 relative to the pipe stub 100. It ispreferable to have the seals 110, 112 seated in annular grooves in theouter surface of the pipe stub 100. As illustrated, the seals 110, 112may be formed from rubber or rubber like o-rings. When the valve 98 isin a closed position (see FIG. 2), the first seal 110 sealingly engagesa sealing shoulder 114 of the valve member 108 and the pipe stub 100proximate an axial side of the inlet hole 102 proximate the distal endof the pipe stub 100. The second seal 112 sealingly engages the valvemember 108 and the pipe stub 100 proximate the main pipe side of theinlet hole 102. When actuated axially towards the main pipe 90 to thesecond position, the valve member 108 disengages from the first seal 110and slides axially past the inlet hole 102, thereby opening the valve 98and fluidly communicating the internal cavity 34 of the standpipe 30with the exterior of the standpipe 30 and the interior cavity 38 of thefilter element 10 when mounted to the standpipe 30.

A coil spring 120 positioned between the end wall 104 of the main pipe90 and the valve member 108 biases the valve member 108 toward theclosed position. To lock the valve 98 in the closed position, the valve98 includes a locking member 122 that includes a plurality of resilientlocking prongs 124. The locking prongs 124 are interconnected to oneanother at an annular common ring portion 126. Each locking prong 124extends radially inward against the pipe stub 100. The locking prongs124 also extend axially toward the end wall 104 main pipe 90. In theclosed position, the distal ends 127, or heads, of the locking prongs124 engage an annular locking channel 128 formed in the outer surface130 of the pipe stub 100 preventing axial movement of the valve member108. Particularly, the locking prongs 124 prevent axially movement in anaxial direction toward the main pipe 90. The interaction of the sealingshoulder 114 and the first seal 110 prevent axial movement away from themain pipe 90 when the valve member 108 is in the closed position.

To open the valve 98, the locking prongs 124 are biased such that thedistal ends 127 disengage the locking channel 128 allowing the valvemember 108 to move axially toward the main pipe 90. The filter element10 biases the locking prongs 124 and actuates the valve member 108between the first and second positions as will be more fully explainedbelow.

In the embodiment illustrated in FIGS. 1-3, the closed end cap 48includes a plurality of keys 136 formed unitarily therewith. The keys136 can be unitarily molded into the inner annular wall 54 of the closedend cap 48. The keys 136 define a plurality of peaks 138 separated by aplurality of valleys that are angularly spaced apart around the annularinner annular wall 54. In an embodiment, the keys 136 taper radiallyinward from a connection interface 142 to the tip 144. The keys 136extend in an axial inward direction, generally parallel to thelongitudinal axis of the filter element 10 and are positioned within thecavity 38 formed by the filter media 40 As illustrated, the connectioninterface 142 of each key 136 has a radial thickness that is generallyequal to the radial thickness of the rest of the inner annular wall 54.As such, radial thickness of the transition from the generallycontinuous portion of the inner annular wall 54 to the key 136 of theinner annular wall 54 is generally equal. Additionally, the keys 136taper angularly such that the keys 136 are generally pyramidal in shape.However, keys having other profiles may be used such as keys having aconstant radial thickness as well as a constant angular thickness. Thenarrowest portion, or terminating portion, of the illustrated valleysprovides a scalloped or rounded profile. However, these portions couldbe flat or tapered. Furthermore, the first end cap may include anynumber of keys depending on the pattern required for the value 98.Furthermore, the key 136 are angularly spaced apart relative to oneanother depending on the pattern of the key receiving slots 148 in thevalve member 108.

The keys 136 function to disengage the locking prongs 124 from thelocking channel 128 thereby allowing the valve member 108 to actuateaxially to change the valve 98 from the closed first position to theopen second position. More specifically, when axially sliding the filterelement 10 onto the standpipe 30 each key 136 passes axially through acorresponding key receiving slot 148 in the valve member 108. The keys136 engage corresponding locking prongs 124 and bias the locking prongs124 out of engagement with the locking channel 128 in the pipe stub 100.Generally, the keys 136 bias the locking prongs 124 radially outward oraway from the pipe stub 100. More particularly, as the keys 136 moveaxially towards the main pipe 90, the keys 136 contact the lockingprongs 124, which are canted relative to the axial movement and apply aradial loading on the locking prongs 124. Once the locking prongs 124disengage the locking channel 128 the valve member 108 is axiallyactuated towards the main pipe 90. The axial actuation of the valvemember opens the valve 98 and fluidly communicating the interior cavity38 of the filter element 10 with the interior cavity 34 of the standpipe30 through inlet hole 102, as illustrated by arrows 152 representingclean fluid flow through the valve 98.

During the actuation of the valve member 108, the coil spring 120 iscompressed such that when the filter element 10 is removed from thestandpipe 30, the coil spring 120 expands and actuates the valve member108 back to the first position, thereby reclosing the valve 98. Further,with the housing cap 22 threadedly secured to the receptacle 20, thecombination axially secures the filter element 10 in a fixed axialposition such that the filter element 10 cannot be axially biased awayfrom the main pipe 90 by the coil spring 122, maintaining the valve inan open position.

After the filter element 10 has been installed and positioned over thestandpipe 30 and the valve member 108 has been actuated to the secondposition, and fluid may flow through the filter system. As illustratedin FIG. 3, dirty fluid, indicated generally by arrows 94, flows into thefilter housing cap 22 and housing receptacle 20 from a dirty fluidsource (not shown) between the filter housing and the outer periphery offilter element 10. The dirty fluid 94 is cleaned as it passes throughthe filter media 40, as indicated generally by arrows 154, and into thecentral cavity 38 of the filter media 40. With the valve member 108actuated to the open position, the clean fluid, indicated generally byarrows 152, passes through the valve 98 and into the interior passage 34of the standpipe 30, as discussed previously, and then returns to thecomponent requiring the fluid.

FIG. 4 illustrates an alternative embodiment of a filter element 210 inaccordance with the teachings of the present invention. The filterelement 210 of FIG. 4 is similar to filter element 10 of FIGS. 1-3 andas such only those features that are different will be discussed indetail. The filter element 120 includes a ring of filter media 240extending between a first end 242 and a second end 244 and includesclosed and open end caps 248, 250 secured the first and second ends 242,244, respectively. However, the end caps 248, 250 do not need to havethe axially inward extending annular walls. In this embodiment, the ends242, 244 of the filter media 240 are directly embedded into plastic endcap material along the interior surfaces 260, 262 of the closed and openend caps 248, 250, respectively. In this embodiment, the end caps 248,250 include disc portions that are generally planar to provide for theembedded filter ends 242, 244. As illustrated, end cap 250 includes aninner lip seal, similar to sealing lip 92 of the previous embodimentthat provides a radial seal. However, other sealing methods could beused such as a seal on the outer surface of end cap 250. Furthermore,seals and sealing lips could be provided by o-rings, felt gaskets, orother similar sealing devices.

The first end cap 248 includes a plurality of keys 236 that extendaxially inward directly from the disc portion. The keys 236 aregenerally similar to and function similarly as the keys 136 of theprevious embodiment. However, in an embodiment, intermittent segments271 of the disc portion are interposed between the keys 236. The surfaceof these disc portion segments 271 are substantially flat and are formedby and generally planar with the inner surface 260 of the first end cap248 in which the filter media 240 is embedded. Furthermore, the keys 236extend directly from the interior surface of 260 of the first end cap248.

Furthermore, in this embodiment, the first end cap 248 includes acylindrical stub 284, or shaft, that extends axially away from thesecond end cap 248 for mounting the filter element 210 to a filterhousing cap similar to housing cap 22 of FIGS. 2 and 3. The stub 284includes a generally frusto-conical portion 292 that forms a head thatis received into a filter mount of a filter housing. In an embodiment,the frusto-conical 292 portion has a maximum diameter that is largerthan the diameter of a connecting wall 294 forming an engagementshoulder that can engage a groove formed within the filter mount of thefilter housing. As illustrated, the stub 284 is generally hollow forminga cavity 293 therein. The cavity 293 can receive the distal end of thepipe stub 100 and also improves molding by maintaining a more uniformmaterial thickness.

All references, including publications, patent applications, and patentscited herein are hereby incorporated by reference to the same extent asif each reference were individually and specifically indicated to beincorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A filter element comprising: a cylindrical ring of filter mediadefining an interior cavity, the filter media extending axially betweenopposite ends; end caps affixed to the opposite ends of the filter mediaincluding a closed end cap and an open end cap, each end cap having aninterior side generally facing the ring of filter media and an exteriorside generally facing away from the ring of filter media, the closed endcap having an inner annular wall and an outer annular wall and a discportion that in combination define an annular well for receipt ofbonding material; cured bonding material in the annular well securingthe closed end cap to one end of the filter media; at least one filterhousing mounting structure on the closed end cap; a plurality of keys onthe inner annular wall extending axially inward toward the open end cap;and wherein the keys form a terminating axially inner end of the innerannular wall and whereby the inner annular wall serves dual functions inlocating keys and damming the bonding material.
 2. The filter element ofclaim 1, wherein the inner annular wall of the closed end cap excludesany base structure projecting radially therefrom.
 3. The filter elementof claim 2, wherein the inner annular wall of the closed end cap has aradial cross sectional thickness that at least remains constant orreduces in thickness as the annular wall extends axially inward.
 4. Thefilter element of claim 3, wherein the keys have a radial crosssectional thickness, and wherein as the keys extend axially inward theradial cross sectional thickness remains constant and/or reduces.
 5. Thefilter element of claim 4, wherein keys form a plurality of peaks andvalleys.
 6. The filter element of claim 4, wherein the peaks areradially and angularly tapered.
 7. The filter element of claim 1,wherein the at least one filter housing mount includes a plurality of aangularly spaced apart resilient prongs extending from the disc portion.8. The filter element of claim 1, wherein the at least one filterhousing mount includes a cylindrical mounting stub having a outwardprojecting shoulder.
 9. The filter element of claim 1 wherein the filtermedia has a media thickness defined by the radial distance between anouter surface of the filter media and an inner surface of the filtermedia, and wherein the distance between the inner annular wall and theouter annular wall of the closed end cap is at least 25 percent greaterthan the media thickness.
 10. The filter element of claim 1, wherein theopen end cap defines a circular sealing lip defining a central openinggenerally coaxial with the inner annular wall.
 11. A filter elementcomprising: a cylindrical ring of filter media defining an interiorcavity, the filter media extending axially between opposite ends; endcaps affixed to the opposite ends of the filter media including a closedend cap and an open end cap, each end cap having an interior sidegenerally facing the ring of filter media and an exterior side generallyfacing away from the ring of filter media, the closed end cap beingformed of plastic material and including a disc portion with an interiorsurface facing the open end cap, wherein one end of the filter media isembedded in the plastic material of the disc portion; at least onefilter housing mounting structure on the closed end cap; and a pluralityof keys on the interior surface of the disc portion and projectingaxially inward from the interior surface of the disc portion.
 12. Thefilter element of claim 11, wherein the closed end cap excludes anyannular walls extending axially inward along the interior cavity. 13.The filter element of claim 11, wherein the keys have a radial crosssectional thickness, and wherein as the keys extend axially inward theradial cross sectional thickness remains constant and/or reduces. 14.The filter element of claim 13, wherein keys form a plurality of peaksand valleys.
 15. The filter element of claim 14, wherein the peaks areradially and angularly tapered.
 16. The filter element of claim 11,wherein the at least one filter housing mount includes a plurality ofangularly spaced apart resilient prongs extending from the disc portion.17. The filter element of claim 16, wherein the at least one filterhousing mount includes an axially outward projecting cylindricalmounting stub having a outward projecting shoulder.
 18. The filterelement of claim 17, wherein the keys are discrete projections formed bya plurality of tapered peaks and valleys angularly spaced apart in acircular configuration.
 19. The filter element of claim 18, wherein thevalleys are substantially flat and co-planer with the interior side ofthe first end cap.
 20. The filter element of claim 11, wherein the openend cap defines a circular sealing lip defining a central openinggenerally coaxial with the inner annular wall.